<HTML>
<HEAD>
<STYLE>
 #first  { display: inline; color: green; }
 #second { display: block; color: red; }
</STYLE>
<SCRIPT>
var id = "first";
function toggleId() {
  var node = document.getElementById(id);
  if (id == "first") {
    id = "second";
  }
  else {
    id = "first";
  }
  node.id = id;
}
</SCRIPT>
</HEAD>
<BODY>
<H1>Changing ID test</H1>
<P>Clicking on the button that follows this paragraph 
should change the layout of <SPAN ID="first">these words</SPAN>
with respect to the rest of the flow.</P>
<FORM>
<INPUT TYPE="button" VALUE="Toggle ID" onClick="toggleId(); return true;">
</FORM>
</BODY>
</HTML>
